This invention relates to a system for mechanically connecting two structural members together, and releasing the connection by electrical means which does not rely on pyrotechnics or other chemical reactions to achieve the separation.
The industry standard for separation of large structural members, (payload fairings, etc.) on large missile systems is ordnance primer cord actuators. Primer cord actuators are well proven with an excellent track record of reliability, but they suffer from certain practical aspects that make their use inconvenient and expensive. Since they are pyrotechnic in nature, there is a potential for inadvertent actuation which is a safety hazard that must be accounted for in use. Those safety hazards are accounted for by operational constraints enforced in the installation and checkout of the pyrotechnic devices, such as interruption of operation and clearing of the area when the ordinance devices are installed and checked out. Likewise, when the unused system is disassemblied, the same safety precautions must be taken to ensure that the pyrotechnic devices are not inadvertently initiated, with consequent injury to personnel in the area.
Pyrotechnic actuators also have certain other disadvantages in use. They often create high shock loads to nearby components, and they pose a contamination potential to delicate instruments and optical instruments. They require EMI shielding to prevent initiation of the ordnance by stray electrical signals. It is often necessary to provide a housing to contain stray mechanical fragments that are generated when the ordnance is initiated. Although the pyrotechnic devices are very reliable, it is difficult to perform an electrical test on the system after it is installed because of the danger of stray electrical signals initiating the pyrotechnic prematurely. Finally, the pyrotechnic devices are limited in temperature range and must be protected against corrosive environments and even water.
The maturity of current aerospace systems demands that the disadvantages mentioned above for pyrotechnic devices be reduced or eliminated. Cost must be reduced and the operational requirements for the installation and checkout and removal of the separation system must be simplified. Finally, the temperature range and environmental conditions in which the separation system must operate must be enlarged and the protections required for the separation system must be simplified or eliminated.